Field
Embodiments relate generally to boron-containing network chalcogenide glass and more particularly to boron-containing network chalcogenide glass which may be useful in IR transmitting applications, such as IR optics, laser or fiber amplifiers doped with rare earths with emission in the near IR, and methods of making the same.
Technical Background
Boron (B) is an extremely useful component of many oxide glasses, including borosilicates, boroaluminosilicates, borophosphates, etc. In the case of silica-containing glasses, B is used as a flux to lower melting/forming temperatures as well as to provide excellent thermal shock resistance through reduced thermal expansion coefficients. In the case of phosphate glasses, B tends to associate with P as a next nearest neighbor, forming coupled BO4/PO4 tetrahedra, which leads to increased polymerization of the glass network and improved durability of the glass.
Although B could be a useful component in tailoring the properties of chalcogenide glass, e.g. to reduce thermal expansion or perhaps to improve chemical durability, there are few reports of B-containing chalcogenide glass. Most of the B-containing glasses that have been reported to date are B sulfide (B2S3) and the so-called alkali thioborates, i.e. glasses comprising B2S3 and an alkali sulfide such as Na2S, all of which are characterized by poor durability. B-containing AgGe sulfide glasses have been described with a passing reference to some unmodified network glasses comprising B2S3 and GeS2. Save for the latter, there are no literature citations for B-containing network chalcogenide glasses, e.g. glasses based on P, Ga, Ge, As, In Sn and Sb sulfides, selenides or tellurides, other than for pure vitreous B2S3, presumably due to the fact that such glasses are typically prepared by melting mixtures of the constituent elements within evacuated fused silica vessels. As B is extremely refractory (Melting Point>2000° C.) as well as very reactive with O, it is very slow to dissolve and has a tendency to react with the container walls, thereby introducing Si and/or O into the resultant melt/glass. There is a need to develop B-containing network chalcogenide glasses, for example, B-containing network sulfide, selenide, and selenotelluride glasses and also methods to overcome the latter practical difficulties.